Mozambican scientist quantifies mangrove carbon to fund coastal protection

Marine biologist Célia Macamo at Eduardo Mondlane University in Maputo is quantifying carbon stored in mangrove soils to create financial incentives for preserving these coastal forests. By collecting and analyzing peat samples — drying, weighing, burning, and reweighing them — she estimates how much carbon dioxide the ecosystems sequester, enabling the sale of carbon credits that reward landowners for protection rather than clearance.

Mangroves near Maputo face pressure from urban expansion, particularly in the Chiango neighborhood bordering the Costa do Sol wetlands, where housing development drives up land prices. Macamo's mapping of mangrove dynamics from 2000 to 2023 shows red patches of loss alongside blue areas of expansion and green stable zones, illustrating the ongoing tension between development and conservation.

The forests provide critical storm protection, as demonstrated when a cyclone struck Nova Mambone: areas directly exposed to the sea suffered 100% mangrove mortality, while a second buffer zone reduced mortality, and a third inland zone remained almost untouched, shielding the village. Their knotted root systems dissipate wave energy, a function increasingly vital as climate change intensifies cyclones.

Beyond storm buffers, mangroves serve as nurseries for marine life, sources of wood and seafood for coastal communities, and significant carbon sinks. Globally, mangrove cover declined from 17.35 million hectares in 1985 to 13.61 million hectares in 2020, often cleared for housing, agriculture, and aquaculture after being dismissed as worthless swamps.

Macamo monitors forest health by measuring tree height, trunk diameter, and salinity levels, noting that high salinity stunts growth and reduces protective capacity. She also studies restoration efficacy, including planting propagules — partially germinated fruits that anchor quickly in soil — to improve regeneration success rates.

After falling in love with mangroves during a 2008 Earthwatch Institute program in Kenya's Gazi Bay, Macamo pursued a PhD in marine botany at Nelson Mandela University. Though administrative duties now limit her fieldwork, she trains coastal professionals in engineering, water management, and impact assessment to integrate mangrove health into their practices.

Macamo observes growing private-sector interest in nature-based solutions, a shift from two decades ago when such investment was absent. "Things are changing," she says, expressing optimism that the financial and protective value of mangroves is finally being recognized in Mozambique.